The present invention relates to frames for insulated glass panels and, in particular, to a cornerpiece for connecting the discrete sections of the frame.
It is well known in the art to provide a window having more than one pane of glass, the panes being separated by an air space. Such windows are known as insulating windows or insulated glass panels by virtue of the fact that the air trapped within the space between the panes of glass serves as an insulator to reduce heat flow through the glass. Typically the panes of glass are separated by a frame comprised of sections of tubing joined together at adjacent ends to form a continuous frame. The frame lies between the panes of glass and extends around the perimeter of the window panes. The tubes, also known as spacer bars, are commonly made of aluminum or steel. In order to prevent the window panes from fogging, it is necessary to keep the air that is trapped between the window panes as dry as possible. A desiccant, for example, silica gel, is oftentimes placed in the spacer tubes to absorb moisture from the air trapped within the space between the window panes. In order to prevent the desiccant from settling to the bottom of the tubular spacer frame when the window is in an upright position, it is necessary to block the ends of the sections of spacer bar to keep the desiccant within the separate sections of the spacer. It is also necessary to block the ends of the spacers to prevent the desiccant from entering the space between the window panes, causing an unsightly appearance.
Earlier cornerpieces were constructed of aluminum or zinc. However, in recent years, to take advantage of lower costs of materials and fabrication, cornerpieces of plastic or nylon have become more common. One such cornerpiece is shown in U.S. Pat. No. 4,530,195 to Leopold issued July 23, 1985. Leopold shows a flexible cornerpiece that has a latching means so that when the corner is formed to its final configuration it is securely latched into position and cannot be unbent without exertion of some substantial force on the corner. It has been found that such positive latching is unnecessary and it is sufficient if the cornerpiece can be temporarily maintained in an angled position during initial construction of the frame. Once the frame is sealed into the final position between the glass panes, the sealant maintains the frame in its correct orientation and configuration without the need for latching of the cornerpiece. It is also desirable to eliminate any moisture path from the end of spacer bar that is provided by seams or voids in the cornerpiece.